Construction And Properties Study Of Environmental Responsive Polydiacetylene Films

This Account describes two works about the polydiacetylene structures, assemblies, thermochromic transition and sensor applications.At first, an azobenzene mesogen-substituted polydiacetylene which self-assembles into stacks with bi-layered structure is investigated in detail by transmission electron microscopy (TEM) as well as X-ray diffraction (XRD). These stacks with bilayer-structure are found to be organized into highly ordered lamellar crystal structures. The substituted polydiacetylene assemblies form a blue phase at room temperature, however, they undergo a well-known thermochromic transition in response to thermal stimulus. In this work, we establish links between chromatic transitions, molecular organization and the morphology of these assemblies. This thermochromic transition has been subjected to detailed investigation by means of Fourier transform infrared spectroscopy (FTIR), XRD as well as TEM. These results demonstrate that the strong intermolecular interaction (Ï€-Ï€stacking) between azobenzene mesogens is essential for complete recovery of chromatic transitions of PDA2 films following thermal stimulation.And on the other hand, it has been known for long time that"blue-phase"PDAs are non-fluorescent while their"red-phase"counterparts fluoresce. For the most part, however, the significance of the different fluorogenic properties of PDAs has been ignored in the context of sensor applications. The development of a novel polydiacetylene (PDA) based sensitive colorimetric sensor microarray for the detection and identification of volatile organic compounds is reported. The organic solvent-dependent colorimetric responses of PDA-embedded polymer matrix have been investigated in detail, which allows for a straightforward"color pattern"procedure to differential between several common organic solvent. Then, multi-layer PDA-based micro patterns have been fabricated by a sol-gel process combined with soft lithography. The structure of multi-layer PDA-based micro patterns is characterized by optical microscope images. Excellent differentiation of closely related organic compounds can be achieved based on cross-responsive sensor array and these systems aim to mimic the mammalian olfactory system by producing composite responses unique to each odorant.